Static eliminators



May 29, 1962 w. c. HERBERT, JR

sTATrc ELIMINATORS Filed Deo. 29, 1958 WILL/AM c. HEME/27,1@

A TTORNE Y Unite States "latent tice 3,037,149 STATIC ELIIVIINATORS William C. Herbert, Jr., 79 Maryland Ave., Freeport, Long Island, N.Y. Filed Dec. 29, 1958, Ser. No. 783,297 1 Claim. (Cl. 3172) I have invented an improvement in electrical units for removing static electricity from sheet material, such as paper or cloth, for example, when such material is passed through machines for processing under conditions which generate electrical stresses.

An important object of my improvement is to provide a static eliminator which can be operated at maximum efficiency and high voltage without danger of sparking or risk of shock to the attendants. Hence the device is perfectly safe in practice.

Another object of this invention is to provide a compact piece of such equipment adapted to be affixed in any suitable location on or adjacent to a machine for treating paper or other material in any form that develops static charges on its surface, and which quickly and completely neutralizes such charges, so that the final product which the machine delivers can be handled with ease and dispatch.

A further object is to provide a static eliminator which is extremely durable, having component parts fully insulated and capable of bearing heavy electrical loads without risk of short circuiting or puncture of parts, or any other impairment, and which is simple and compact, can be produced at relatively low cost, and very readily installed in the required position.

In the description the construction of the eliminator of this invention is fully explained and the drawings show the best embodiment of my invention now known to me. The novel characteristics are in the appended claims, but this disclosure, however, is by way of example only, and changes in structural details may of course be adopted without omitting or materially altering any of the essential features of the general design or principle of operation which distinguishes the invention.

In the drawings:

FIGURE l is a longitudinal sectional View of an eliminator according to my invention.

FIGURE 2 is a top plan of the eliminator.

FIGURE 3 is an end elevation thereof, as it appears from the supply end.

FIGURE 4 is a side View thereof.

FIGURE 5 is a diagram showing how the eliminator is connected in an operating circuit.

FIGURE 6 is an end View of the eliminator and ground wire therefor, with the unit in position adjacent the material being neutralized.

FIGURE 7 illustrates how the ground connection is preferably established in practice.

FIGURE 8 is an end elevation of an end cap for the eliminator which is part of the ground connection.

The static eliminator or neutralizer bar or rod has an elongated body indicated as a whole at 1. It carries a plurality of short insulated electrodes 2 projecting therefrom and arranged in a straight line at separated points along the length thereof. The body is mounted so that it lies crosswise of a length of sheet material passing it with the outer ends of the electrodes 2 presented to the surface of said material and at short distance therefrom.

The bar is disposed so as to be energized from a high tension step-up transformer 3 connected to the unit by a cable 4 having a conductor 5 inside; one extremity of the cable being within the bar and the other protruding from said body. The transformer is coupled to a supply circuit having suitable switches, not shown. The conductor or wire 5 in the cable 4 has a covering of insulation 6, and an outer sleeve or sheath 7 of polyethelene, vinyl or some other suitable insulation. Cables of this type are well known.

The eliminator also comprises a tubular outer casing 8 of insulation with high dielectric strength, with openings at various points for the studs 2. The cable 4 enters the body 1 at one end, and the opposite end is closed by an insulator plug 9, preferably of polystyrene, which is hollow at its inner extremity to receive a polyethylene cap 10 which fits upon and is fused to the end of the insulation 6 in the cable 4. Within the casing S the cable is enveloped by an insulator sleeve or tube 11 which abuts the plug 9, but the opposite end of the tube 11 is overlapped by the casing 8. The end of the casing 8 at the cable connection contains a hollow conical plug 12, split along its length, forming a locking clamp or bushing.

Within the casing S the tubular member or sleeve 11 has small metallic coatings or 'films 13 so located when the parts are assembled that each film or coating is in line with one of the studs 2. The coatings may consist of metallic paint on the member 11 and of course are conductive, and adhere to the member 11. The sleeve 11, and coatings 13 constitute a capacitor carrier, adjacent the cable 4 and effectively removes the static from the sheet material 24, which passes over the eliminator, as indicated in FIGURE 6, at the proper distance, which is preferably somewhat less than one inch, but may be greater, if necessary.

The studs pierce the tubular casing or member 8 from the inside and project a short distance from the casing 8. 'Iheir inner ends are in actual contact with the lms 13 of the member 11, which is wholly within the casing or member 8.

On the ends of the body 1 are plastic rings 14 which encircle the casing 8 at each end, the rings being ilush with both ends of the casing 8, the cable clamp 12, and the plug 10. These rings are spanned by metal ground plates 15 which are curved crosswise concentric with the round casing 8, and are secured by screws 16 to the rings 13. These plates are connected to ground 17 as indicated in FIGURE 6. The plates flank the electrodes 2, which are located midway between the plates 15.

As is well known, static is a surface charge of elec# tricity generated by friction on paper or other sheet material. It is always due to an unbalanced condition of electrons on the sheet, arising as surfaces in contact are separated. When the surface of paper, cloth, plastic, etc, is in close contact with another surface, as, for example, when the sheet passes over or around a roller, electrons intermix at the contact area. As the surfaces separate, some of these electrons are caught off base, due to the non-conductive nature of the material. The resultant excess or deficiency of electrons is static.

I overcome static with my eliminator by causing ionization of air between the emitter points of the electrodes 2 and the surface of stock on which static is present. Release of free electrons from air molecules is caused by application of high voltage at the emitter points. These free electrons strike other molecules, release more electrons frorri them, and -a flow of electrons, with a corresponding residue of particles from which electrons have been released then ensues.

When a static charge on the surface of paper, etc., passes such ionized air, the charge is instantly overcome by the passage of electrons in this ionized, or conductive, air. Excess electrons pass to ground through guard plates 15 and machine parts, leaving the surface of the sheet, completely freed of static.

In practice, high voltage amounting to thousands of volts is applied at the emitter points of electrodes 2, but elimination of static is accomplished with such control 3 of the quantity of electrical current that no shock, sparking or arcing occurs. Operators are in no danger of injury. The lms 13 must be such size extending along tube 11 as to obviate danger of sparking and still produce enough ionization.

FIGURES 7 and 8 indicate another method of establishing a ground connection for the eliminator. A metal plate 18 from the center of which projects a tubular metal sleeve or bushing 19 is tted to the end of the body of the eliminator, this plate having overturned, separated, rounded rims 20 of metal of such length that they will tit over the ends of the ground plates 15. The tting 18 grips the end of the eliminator body firmly; and the power conductor 4, which is connected to the transformer, passes into the eliminator through the sleeve 19. The transformer casing of metal is indicated at 21 with an opening surrounded by a metal nut bushing 22, which is closed at one end by a metal coupling or cap nut 23. Between the eliminator and the transformer casing, the cable is enveloped in a shielding metal cover 24', and of course, the conductor 4 and the cover 24 are of any desired length. In practice, the transformer casing can be installed on the wall, ceiling, or frame of the machine; and the ends of the cover 24 at the casing 21 `are split as indicated at 25. The portions 25 are under the nut 23, and gripped in contact with nuts 22 and 23. The opposite end of the cover 24 makes contact with one end of the sleeve 19, and thus a ground connection will be established. In the nut 22 and casing 21, the conductor is surrounded by suitable insulation, diagrammatically indicated at 26. Any suitable well known means can be utilized to connect the conductor 4 to the positive terminal of the transformer in the casing 1.

The transformer is a step-up transformer, the primary of which can be connected to an ordinary 110 volt, 60 cycle source of current or other supply, and the secondary will increase Voltage up to 15,000 volts or any desired amount.

The ends of electrodes 2 should be the correct distance from the surface of the stock 24 (above or below) depending upon material and nature of the installation. See FIGURE 6.

The invention is thus of the best and most efficient design and well suited to serve the purposes for which it is designed.

The polyethylene cap keeps the end of the cable in the plug 9 completely and permanently insulated. In the absence of a cap 10 of this or equivalent material, the plug 9 would soon permit leakage of electricity and danger of shock would arise. When finished as above described, all risk of sparking and shock are obviated. The tubes 8 and 11 yare of the best insulation, preferably paper or other bre as a base, and phenolic resin laminations.

The eliminator is most effective in practical operation and even when working at the highest voltage for which it is designed the attendant will receive no shock even if he touches the points of the electrodes 2.

Other methods of establishing ground connections may be used.

Having described my invention, what I believe to be new is:

A static eliminator comprising a tubular member of insulation, a plurality of electrodes carried by said member and projecting through said member from the interior to the exterior thereof, said electrodes having pointed extremities on the outside of said member, a cable containing a conductor enveloped by insulation within said member, a tubular sleeve of insulation enveloping said cable Within said member, electrically conductive films spaced from one another on said sleeve adjacent each of said electrodes, the conductor projecting from the cable at one end within said member, a cap for said end and a plug having a recess enveloping said cap and adjacent portion of the cable, the opposite end of said eliminator having a tapered, split bushing entering said opposite end to secure the cable and sleeve therein, insulator rings encircling the ends of said member, conductive plates joining said rings and extending between the ends of said member and spaced apart, flanking the line of electrodes, and a ground connection for said plates.

References Cited in the le of this patent UNITED STATES PATENTS 940,431 Chapman Nov. 16, 1909 1,489,425 Chapman Apr. 8, 1924 1,663,466 Rostal Mar. 20, 1928 2,087,915 Kimball July 27, 1937 2,392,808 Chapman Jan. 15, 1946 2,866,923 Herbert Dec. 30, 1958 

